In many automobiles, especially those made by the General Motors Corporation, the dwell time of the ignition system is adjustable by turning of an adjustment screw located within the distributor and accessible through a small access door leading into the distributor. Often, access to the door is difficult due to obstructions surrounding the distributor and because of the nearness of the distributor to the fan. Wrenches supported at the ends of flexible cables have been devised as tools for adjusting the dwell time as an engine is running, but such cable-driven tools are difficult to use because of the limited flexibility of the cables and because the vibrations from an operating engine tend to make the tools fall out whereby the tools may become dangerously fouled in the fan blades. Moreover, since a mechanic in the process of adjusting the ignition system of an automobile must observe a dwell meter and must manage a strobe light to see the timing mark and must also adjust the timing, it is difficult to also manually hold a cable wrench in position to keep it from falling out of the distributor. Further, it is often difficult to open the small door into the distributor, particularly while the engine is running, and to hold the door open while the wrench end of the cable is inserted.
A simple and inexpensive wrench which would open the access door in the distributor so as to permit entry of a hexagonal wrench end, which would not fall from the engine because of engine vibration, which would easily pass into the cramped quarters surrounding a distributor access door, and which could be left in place unattended while a mechanic attended to other duties, is much to be desired.